1. Field of the Invention
The present invention relates to tuning devices for musical instruments, and-more specifically, to electronic tuning devices employing LED displays for indicating the tuning of almost any type of musical instrument including stringed percussive instruments such as guitars, pianos, harps, etc., and electronic musical instruments which have microphone pickups and amplifiers to generate acoustical sound vibrations in the air by speakers.
2. Description of the Prior Art
Traditional tuning of instruments is often done with one or more tuning forks, or other accurate tone sources, and a trained ear. In this process, the artisan often uses the phenomenon of "beats" to fine tune the instrument. A beat is an apparent oscillation of the loudness of a perceived tone when that tone is produced by two simultaneous tones of nearly, but not exactly the same frequency. Beats occur at a frequency equal to the difference between the two generating frequencies. For example, if a tuning fork is vibrating at a frequency of 440 Hz (440 cycles per second or in musical terms an A note) and a piano string is simultaneously vibrating at a fundamental frequency of 443 Hz, a definite rising and falling in the volume of the perceived tone will occur at a rate of three cycles per second. As the two tones approach the same frequency the beat frequency will reduce to zero. At a beat frequency of zero there is simply no variation in the volume of the combined tone. When a beat frequency occurs there is no way to tell which of the two tones (the tuning fork or the piano) is the higher frequency. When a three Hertz beat occurs the technician can only be sure the string is three Hertz off from the standard tone. Whether the string is sharp or flat still had to be determined by ear. Many times a trial adjustment was made and if the beat got faster, the knowledge was gained that the adjustment was in the wrong direction. The traditional method of tuning instruments left a lot to be desired and was entirely dependent on the skill of the tuning technician.
An electronic tuner for musical instruments has been marketed by Sabine Musical Manufacturing Company, Inc. of Gainesville, Fla. since about 1987. For tuning traditional musical instruments, i.e. non-electronic instruments, the tuner is set on a table top and uses a built-in microphone to sense tones produced by the musical instruments. For tuning electronic instruments, a signal output from the instrument or amplifier is directly connected by a cable to the electronic tuner. The LED display of this prior art tuning device consists of a bottom row of twelve lights corresponding to the twelve musical notes in an octave, i.e. A, A.music-sharp. (B.music-flat.), B, C, C.music-sharp. (D.music-flat.), D, D.music-sharp. (E.music-flat.), E, F, F.music-sharp. (G.music-flat.), G and G.music-sharp. (A.music-flat.). A separate top row of three lights is provided for indicating flat, in-tune or sharp tuning conditions, respectively. The flat and sharp error indicating lights are operated at blink rates proportional to the magnitude of error. During tuning the musician must constantly monitor both rows of LED's, and in the absence of such concentration, a change to the wrong note can be overlooked resulting in tuning of the instrument or string to the wrong note.
Electronic tuning devices of the above type work best with the electronic instruments where electrical signals from the electronic instruments are fed directly into the tuning device circuitry. Use of a microphone to pickup the tone from air-transmitted sound from acoustic instruments is susceptible to error or difficulty in tuning due to ambient noise also picked up by the microphone. Such ambient noise or interfering tones are subject to being confused by the tuning device with the tone being transmitted by the instrument resulting in failure or difficulty in obtaining a tuning indication from the tuning device.
The prior art, as exemplified by U.S. Pat. Nos. 4,018,124 (Rosado), 4,319,515 (Mackworth-Young) and 4,899,636 (Chiba et al.), contains a number of devices which are mountable on musical instruments for providing a display useable in tuning the instruments. Rosado and Chiba et al. are mountable on guitars with Chiba et al. being releasably mounted by a sucker and having a rubber vibration inputting member serving to prevent noise. The Chiba et al. tuner case has a resonant frequency characteristic functioning as a low-pass filter to attenuate higher harmonics of the fundamental frequency.
U.S. Pat. Nos. 4,648,302 (Bozzio) and 4,984,498 (Fishman) disclose mounting acoustic transducers on drums by double sided adhesive foam rubber tape. Bozzio states that re-attachable adhesives can be used. Additionally Fishman employs a silicone RTV adhesive on the transducer for dampening high-frequency resonances.